In a storage phosphor imaging system as described in U.S. Pat. No. 31,847, reissued Mar. 12, 1985, to Luckey, a storage phosphor, also known as a stimulable phosphor, is exposed to an x-ray image of an object, such as the body part of a patient, to record a latent x-ray image in the storage phosphor. The latent x-ray image is read out by stimulating the storage phosphor with relatively long wavelength stimulating radiation such as red or infrared light produced by a helium neon gas laser or diode laser. Upon stimulation, the storage phosphor releases emitted radiation of an intermediate wavelength, such as blue light, in proportion to the quantity of x-rays that were received. To produce a signal useful in electronic image processing the storage phosphor is scanned in a raster pattern by a laser beam deflected by an oscillating or rotating scanning mirror or hologon. The emitted radiation form the storage phosphor is reflected by a mirror light collector and detected by a photodetector such as a photomultiplier to produce an electronic image signal. Typically the storage phosphor is translated in a page scan direction past the laser beam which is repeatedly deflected in a line scan direction perpendicular to the page scan motion of the storage phosphor to form a scanning raster pattern of a matrix of pixels.
Where different size storage phosphors are scanned the scanning raster pattern size can be changed so that the scanning pixel size changes. This results in less stimulating light reaching the storage phosphor and consequent less emitted light to be detected as pixel size decreases. U.S. Pat. No. 4,568,973, issued Feb. 4, 1986, inventor Ishida, discloses a radiation image reproducing system in which the size of the stimulable phosphor sheet is detected, the scanning line density of the stimulating ray and the reproduction scaling factor are changed according to the storage phosphor sheet size to reproduce an image of approximately equal size and resolution on a recording media of a fixed size. The problem of changing levels of emitted light as pixel size changes is not addressed in this patent.
There is thus a problem in the prior art of compensating for different light emission levels produced by changing scanning pixel size for different size storage phosphors.